Is the same thing that the multitouch driver. We are waiting for an apple update of EFI that resolves this problem, but apple not response for this noise because they say that is only perceptible in windows. The most volume in that type of sound is in the LED Screens that are 17' and hi-res, because are bigger and have more leds, so, more leds, more noise. This problem is in all macbooks screen, LCD incluyed but in that remplacing the inverter the sounds descends.
In Leopard is a sound that we not listen because is not 'high noise'. That`s because in windows we have a noise that if we are in front of the macbook pro, in the right ear we listen a buzz low noise that in 50% of brightness is the most perceptible.
The think is that Leopard manage the brightness using other system than windows. The think of the question is that: The LED Screens don´t have inverter, the brightness is regulated by the power that the logic board provides to the screen.
I am an user of the macbook pro 17 (early2008), the model with the 8600 GT 512.
